Generally speaking, replaceable/expendable inserts secured in a reusable steel body are preferred to one-piece cutting tools in which the tool body has built-in sharp cutting edges. One-piece tools have been dominant at a low end of the tool-size/diameter scale. Specifically, this is true under a certain insert size, where it becomes impractical (or even impossible) to use replaceable inserts because they cannot be secured in a pocket via a clamping screw which normally passes through a clamping bore in the insert. The main reason for this, is that under a certain size, the clamping screws (and specifically the heads thereof) become too small for standard drivers or wrenches.
Another, and perhaps more important problem with replaceable/expendable indexable inserts is that it is very difficult to handle such small, barely-visible units by hand. The milling kit of the present application, and specifically the magnetic positioning tool, overcomes these problems and offers a milling tool with replaceable undersized milling inserts.